hi, i am new to linux. i want to know what happens to the older kernel when i install a new kernel? does it overwrite? also explain me how do i find the path/location for both older and newer kernels! please help!

@rohit, newer installed kernels do not overwrite existing kernels unless you delete them explicitly. So you can always choose to boot with the proved old one :-) As for the kernels location, it depends on where do you install them… In my case I always create a /boot partition, so there you could find all those kernels… Best of luck!